US2106939A - Crankcase for internal combustion engines - Google Patents

Description

Feb. l, 1938. K. wlLcKEN 2,106,939

CRANKCASE FOR INTERNAL COMBUSTION ENGINES Filed April 2, 1936 Patented Feb. 1, 1938 UNITED STATES PATENT OFFICE Karl Wlcken, Dessau-Ziebigk, Germany, as-

signor to Junkers Flugzeugund Motorenwerke Aktiengesellschaft, Dessau, Germany Application April 2, 1936, Serial No. 72,256 In Germany April 10, 1935 3 Claims.

My invention relates to crankcases for internal combustion engines, and more particularly to Aan improved crankcase for engines, in which the cylinders or series of cylinders are arranged on opposite sides of the crankshaft.

Internal combustion engines of the type aforesaid are preferably used in vehicles and in view thereof the crankcases of such engines must conform to numerous requirements.

In order to meet these requirements the crankcase must be formed as a rigid girder, which is not deformed to any noticeable degree`by the forces acting on it, thus preventing the obnoxious jamming of the crankshaft in its bearings, which are rig-idly connected with the crankcase. Apart from the requirements as to strength to which the crankcaseis subject, requirements of operation must also be considered and in particular provisions must be made for adapting thecrankcase structure for a ready insertion and removal of the crankshaft.

It is an object of the present invention to combine the cylinders or seriesof cylinders in an engine of this type into a self-contained unit.

It is a further object of my invention to provide a crankcase, which permits of an easy insertion and removal of the crankshaft, e. g., for repair purposes.

According to the present invention the crank- 0 case is formed as an integral casting of U-shaped cross section, in which the legs extend parallel to the plane passing through the cylinder axes. One of the opposed cylinders or cylinder series is attached to the bottom of the u -shaped case,

5 while the other cylinder or series of cylinders is or are mounted on the free ends of the U-legs in a manner such that these legs are braced rela- 1 tive to each other. The crank bearings arranged on the inside of the case bottom are each prol vided with a bearing cap separately. inserted in the U-cavity, and present a joint, which extends at right angles to the mean plane of the cylinders.

A crankcase of this kind involves great advantages in engines of the opposed cylinder type.

I n cooperation with the cylinders, it provides the required rigidity in the various dimensions, and in. spite of its integral structure renders possible an easy insertion and removal of the crankshaft, after the cylinder or cylinder series arranged on the open side of the U-structire have been re` moved.

In the drawing aiii'xed to this specication and i forming part thereof two embodiments lof this invention are shown diagrammatically by way of example.

In the drawing Fig. 1 is a section at right angles to the crankshaft and in the plane of the cylinder axes of two 5 opposed cylinders,

Fig. 2 is -another section at right angles to the crankshaft taken, through the space between two adjacent cylinders, e. g., on the line II-II of Fig. 3, and

Fig. 3 is `a section longitndinal with respect to the crankshaft and at right angles'to the cylinder axes, e. g., on the line III--IlI in Fig. 1, of one embodiment of the invention.

Fig. 4 is a section, similar to that shown in 15 Fig. 2, of another embodiment.

Referring to the drawing and first to Figs. 1, 2 and 3, I and .2 are the opposed cylinders or cylinder series of an internal combustion engine. The opposed cylinders are connected with each other by an integral crankcase 'of U-shape, the U being formed by the bottom portion 4 and the two legs 4a and 4b. These legs extend parallel to the plane passing through the cylinder axes.

The cylinder or cylinder series I is mounted by means of the iiange 5 on the free ends of the legs 4a and 4b of the crankcase, forming a brace for these two legs. The cylinder or cylinder series 2 is mounted by means of the flange 6 on thek bottom portion 4 of the U-shaped case.. The 30 cylinders or cylinder series l and 2 are attached to the crankcase 4, 4a, 4b by means of screws, which are either fixed, according to Figs. 1-3, in the crank case in the form of stud-bolts 3, or which are provided, according to Fig. 4, in the form of bolts I3 which intersect the case in the direction at right angles to the crank shaft and by means of nuts hold each cylinder or cylinder series in position on the crankcase.

0n the inside of the bottom 4 of the U-cavity 40 formed by the case section the crank bearings are arranged, and are divided on a. plane at right angles to the cylinder axes. 'Ihe pedestal bodies 'I are formed integral with the sides and bottom of the crankcase structure and braced by walls -or` ribs 8, while the bearing caps I0 are inserted in the case from the open side thereof and are fastened to the pedestal bodies T by means of the screws indicated at 9. In order to close, on one hand, the cavity of the U-structure, and to faclli- 5. tate, on the other hand, insertion and removal of the crankshaft, the front faces of the case are formed with removable covefs or end plates I I, l2. This design of the crankcase and crank bearings allows an easy insertion and removal of the crank- 5,,

shaft after removal of the cylinder or cylinder series I mounted on the legs and the simultaneous removal of the covers II, I2. This design of a crankcase further offers the advantage that the lowest'bearing pressures occur in the plane of the bearing joints. The upper portion of the crankca'se-comprlsing the leg la may be formed, between the bearings, with perforations I4, which are preferably closed by a light cover I5. The lower part oi' the crankcase comprising the legs 4b is formed with an outer wall I8 extending over thelength ofthe case and is preferably troughshaped as indicated 'in Figs. 1, 2 and 4. This portion may form the oil sump.

Numerous advantages are connected with the novel crankcase according to the present' invention. It complies with all requirements as to strength to which a crankcase chiefly used in connection with vehicles is subjected. The crankcase is assembled in a self-contained unit, which displays all the. advantageous characteristics of a unitary structure, such as a saving of space and y Various changes may be made in the details disclosed in the foregoing specification without departing from the invention or sacrificing the adf vantages thereof.

I claimt- '1. An internal combustion engine in which the cylinders are arranged on opposite sides of the crankshaft, comprising in combination, a crank- 'case forming a unitary structure having, at right angles to the crankshaft, the cross-section of an U, the legs of which extend parallel to the plane passing through the cylinder axes, a series of cylinders mounted on the bottom of said U -shaped structure and a series of cylinders mounted on the free ends of the legs of the crankcase so as to brace the legs relative to each other, crank bear'- ings arranged on the inner side of said bottom and formed with a. joint extending at right anglestothe mean cylinder plane and a bearing cap for each crank bearing separately mounted in the cavityyof said U-shaped structure.

2. An internal combustion engine in which the cylinders are arranged on opposite sides of the crankshaft, comprising in combination, a crankangles to the crankshaft, the cross-section of an U, the legs of which extend parallel to the plane passing through the cylinder axes, a cylinder vcase forming a unitary structure having, at right v mounted on th bottom 'of said U-shaped struc- ,cylinders are arranged I.on opposite sides of the crankshaft, comprising ifn combination, a crankc'ase forming a unitary structure having, at right angles to the crankshaft, the cross-section of an U, the legs of which extend parallel to the 'plane passing through the cylinder axes, a cylinder mounted on the bottom ofvsaid U-shaped strucp ture and a cylinder mounted on the free ends'ot the legs of the crankcase so as to Abrace the legs relative to each other and removable covers bridging the gap between the legs on either side of the' 'U-shaped structure.

KARL WImKEN.

Images