US2287399A - Internal combustion engine - Google Patents

Description

June 23, 1942. E ETAL I 2,287,399

INTERNAL COMBUSTION ENGINE Filed Dec. 23, 1959 2 Sheets-Sheet l IN VENTORS Marsqien Ware BY Mar'vm J. Steele June 23, 1942- M. WARE ETAL ,287,399-

INTERNAL COMBUSTION ENGINE Filed Dec. 23, 1939 -2 Sheets-Sheet 2' INVENTORS Marsden Ware, BY Marvin J. Steele ATTORNEYS Patented June 23, 1942 INTERNAL COMBUSTION ENGINE Marsden Ware, Huntington Woods, and Marvin J.

Steele, Detroit, Mich., assignors to Packard Motor Car Company, Detroit, Mich., a corporation of Michigan Application December 23, 1939, Serial No. 310,676

4 Claims.

This invention relates to internal combustion engines and more particularly to engine crankcases having angularly disposed cylinders associated therewith.

Crankcases of this type, especially those with which the cylinders are in V-relation, usually support the crankshaft in bearings arranged along one terminal of transversely extending Webs or walls and a sheet metal closure member for the crankshaft is applied to such wall. This closure member'is not designed to absorb load and consequently the crankshaft supporting half of the case structure must absorb substantially all loads resulting from explosions. The stresses are rapidly reversed at high engine speeds and the casing wall structure must be strong enough to Withstand all operating stresses.

In the interest of reducing the crankcase weight and increasing its stress resistance, it isthe practice to secure the crankshaft bearing .20

caps by tension bolts that extend through the bearings and the supporting webs to the exterior of the crankcase in parallel relation with the axes of the cylinders. Such bolts are placed in tension so that explosion loads on the crankshaft bearings and the associated webs caused by explosions in the engine cylinders will be well distributed.

While this bearing cap securing arrangement allows reduction in crankcase wall thickness due.

to the compression of the crankcase webs in directions parallel with the axes of the cylinders, the crankcase webs extending outside of the tie bolts are not materially compressed and unless made relatively thick they become fractured under the explosion loads.

One of the objects of the present invention is to provide an engine of the character designated in which the crankcase is placed under compression in directions of the axes of the cylinill ders and also transversely of the crankshaft bearings.

Another object of the invention is to provide an engine of the character designated in which loads on the crankcase and its transversely extending webs, caused by explosions in the engine cylinders, are'taken directly by members in tens1on,

Another object of the invention is to provide a light-weight engine crankcase in which the walls and webs can be made thin through the employment of a plurality of tension members ing for crankshaft 2|.

(01 121-194) I are flanged to assist in directions of themajor' stresses.

Other objects of the invention will appear from the following description taken in connection with the drawings, which form a part of this specification, and in which:

Fig. 1 is a. transverse vertical section through a portion of a V-type internal combustion engine with parts broken away;

Fig. 2 is a sectional view of the engine taken on line 22 of Fig. 1;

Fig. 3 is a sectional view of the engine taken on line 3-3 of Fig. 1;

Fig. 4 i a perspective view of bearing cap;

Fig. 5 is a sectional view of a crankcase similar to Fig. 1, showing a modified form of web;

Fig. 6 is a sectional view taken on line 8-6 of Fig. 5.

Referring to the drawings, Ill indicates generally the crankcase or an internal combustion engine on the angular. top wall ll of which an- .gularly disposed pairs of cylinders l2 and I3 are secured by bolts H. The crankcase is in the form of a shell having lugs l5 extending from the side walls It thereof by means of which the engine may be mounted and secured upon a suitable base, The lugs are preferably cast integral with the crankcase and extend horizontally.

The crankcase is'provided with transversely extending internal Webs l1 preferably cast integral therewith and arranged one between each pair .of cylinders. The webs are provided-with a crankshaft suitable openings H to lessen their weight and 'theaxis of theadjacent cylinder. .The central bottom wall portion 19 of the webs lying between the angular faces is formed as a semi-circular bearing to receive the upper section 20 of a bush- The bottom wall faces22 of the webs adjacent the sides of the crankcase extend horizontally and are joined with the angular faces ill by vertically extending faces 22'.

disposed in at least three angular relationships.

A further object of the invention is to provide a crankcase structure in which the interior webs The bottom wall of the crankcase is 'covered by' a removable sheet metal pan 23 forming a sump for the engine lubricating system.

Beneath each of the webs I1 is arranged a bearing cap 24 which maybe formed of suitable material. Such caps each have faces 25 and 26 respectively complementaryto the web faces I8 and 22', and an intermediate semi-circular face 21 adapted to receive the lower crankshaft bushing section 28.

Each crankcase web l1 and its associated cap through the side walls of the crankcase.

24 is provided with a pair of aligned holes 29 in which tension members 30 are disposed. These members 30, preferably in the form of tie bolts, extend through the holes in the caps and the webs and through the upper crankcase wall H where they are secured'by nuts 3|. By turning the nuts down on the bolts, after engaging the crankcase, the bolts will be placed in tension so that the crankcase will be held in compression in the direction of the axis of the bolts. Obviously the bolts will also serve to secure the bearing caps in assembled position. The nuts 3| may be provided with any suitable locking means such as the lock nuts 32. These tension bolts add strength to the crankcase so that it can withstand greater stresses in the axial zone of the cylinders.

The portions of the webs extending outside of the bolts 30 are subjected to deflection and fracture induced by bending movements resulting from periodic forces existing in the crankshaft as the cylinders are fired alternately in the respective cylinder banks. In order to permit the use of a thin web and still overcome this condition without materially increasing weight, it is proposed to provide reinforcing ribs and also tension means for placing the webs in compression horizontally.

The sides of the caps. are provided with vertically extending undercut grooves 33 for anchoring the heads of tension bolts 34 that extend horizontally through openings 35 in the webs and Nuts 35 are screwed on the threaded outer ends of the bolts against the casing side walls sufli'ciently to compress the web portions through which the bolts extend. The grooves 33 are coextensive with the side portions of the caps so that the bolts 34 can be positioned in the webs prior to assembly of the caps. These tensioned bolts 34 serve to secure the bearing caps in assembled position with the'webs as well as placing the crankcase under compression in a horizontal direction.

As a further means of strengthening the thin webs in the crankcase, integral flanges or ribs are provided. One such rib 40 follows the outline of the bottom face of each web and projects beyond both vertical faces thereof in a direction axially of the crankshaft; Each web is further reinforced by flanges or ribs 4| extending at an angle to the horizontal and joining ribs 40 with the side walls of the crankcase preferably about midway between the adjacent bolts 30 and 34. As shown in Fig. 1, these reinforcing flanges 4| extend upwardly from the horizontal in a direction away from the adjacent crankcase side wall while'in Fig. such flanges 4| extend downwardly from the horizontal in a direction away from the adjacent side wall of the crankcase. Such ribs will reinforce the webs to resist fracture under load resulting from applied crankshaft forces.

With the tension means herein described the crankcase is placed in compression in a plurality of directions radially of the crankshaft. Because of such tension means and reinforcing ribs, the walls of the crankcase can be made relatively thin without danger of fracture from explosion-induced forces.

Although the invention has been described in connection with a specific embodiment, the principles involved are susceptible of numerous other applications which will readily occur to persons skilled in the art. The invention is therefore to be limited only as indicated; by the scope of the appended claims.

What is claimed is:

1. An internal combustion engine casing comprising a crankcase shell having angularly disposed pairs of cylinders fixed on the top wall thereof, relatively thin webs formed integral with the shell and extending transversely thereof in planes between the adjacent pairs of cylinders, said webs having a bottom face with a central crankshaft bearing portion and portions adjacent the bearing portion extending outwardly and downwardly, bearing cap structures having faces complementary to and bearing against the outwardly and downwardly extending portions of the bottom faces of the webs, angularly disposed bolts of relatively large diameter extending through the shell, the webs and the cap structures in a relation parallel to the axes of the pairs of adjacent cylinders and outside of the crankshaft bearing portions thereof, means securing the bolts in tension to compress the caps, webs and crankcase adjacent thereto, bolts anchored to the bearing caps outside of the angularly disposed tension bolts and'extending horizontally through the webs and the shell, and securing means applied to the ends of the horizontally extending bolts exteriorly of the shell in a relation to place the bolts in-tension and holding the portions of the webs and crankcase adjacent-the horizontal bolts under compression.

2. In an internal combustion engine, a crankcase having two rows of cylinders in angular relation thereon, webs integral with and extending across the interior of the crankcase between the pairs of cylinders in the two rows, the base walls of the webs each having a crankshaft bearing portion above the bottom of the crankcase and extending downwardly at an angle normal to the cylinder axes at each side of the bearing and then vertically to form angular seat portions, a bearing cap having angular and vertical wall portions complementary to and bearing against portions of each web, the vertically extending wall portions of the caps having undercut grooves therein, a pair of angularly disposed bolts extending through each associated web and cap and the crankcase in parallel relation to the respective cylinder rows, said bolts passing through the downwardly extending base portions of the webs and caps outside of the bearing portions thereof, said bolts compressing portions of the crankcase, webs and caps adjacent thereto, a second pair of bolts extending through the portions of each web lying outside of the vertical seats and to the exterior of the crankcase, the

heads of the second pair of bolts lying in the undercut grooves in the caps, and means acting on said latter bolts to place the portions of the web and crankcase adjacent such bolts in compression.

3. In an internal combustion engine, a crankcase having angularly disposed cylinders mounted thereon and having transverse integral webs for supporting the crankshaft bearings, said web having a bearing receiving recess and formed with angular faces extending from said recess and with separated parallel faces extending vertically from the outer ends of said angular faces, a bearing cap for each web formed with a bearing recess and having angular and separated parallel'faces complementary to the angular and parallel faces of said web, said cap filling the space between the parallel faces of said web, bolts parallel with the cylinder axes extending through said cap and web securing the cap in place around the crankshaft bearing, and separated substantially aligned bolts connected to the cap therein, a cap having a. complementary bearing recess and having portions extending laterally thereof, said portions each having vertical undercut grooves thereln, bolts mounted horizontally in the webs laterally of the bearing recesses and having their heads separated substantially the distance between theundercut grooves of the cap so that thebolt heads will enter the grooves as the bearing cap is m'oved upwardly into place.

' means arranged between the bearing recess and said grooves for securing the bearing cap in position, and means operating with said bolts to 10 clamp the bearing cap to the web.

MARSDEN WARE. MARVIN J. STEELE

Images