EP0771944A1 - Crank case for an internal combustion piston engine - Google Patents

Abstract

The casing has a metallic inner section (1) with cylinders (3,4). The inner section has integrally formed liners (5,6), consisting of the same material. The liners extend between an upper connection plane for the cylinder heads, and a plane, which is located between a lower connection plane and a cover plate (7). Cast stiffening bridges (17) are located in the area of the cover plate between the liners and the screw posts (8). The cover plate has a circumferential claw connection section (20), and a corresponding part of the outer casing section is cast around this.

Description

The invention relates to a housing for an internal combustion engine according to the preamble of claim 1.

A generic housing is disclosed in DE-34 36 872 C2. This housing for a single-row internal combustion engine has an inner part which is common to all cylinders and consists of gray cast iron and has a cover-like bottom. Adjacent to individual cylinders, screw pipes extend between an upper connection plane carrying a cylinder head and a lower connection plane receiving a longitudinal axis of the crankshaft.
The floor arranged between these levels is closer to the lower connection level and is surrounded in the longitudinal direction of the internal combustion engine by side webs arranged between the screw pipes and connected to it. Between two screw pipes arranged in a transverse plane of the internal combustion engine, a wall extends from this floor to the lower connection plane, which serves to support the crankshaft.
In the area of each cylinder, the floor has a circular recess, in which liners are inserted separately.
To achieve a housing that is as light as possible, this inner part is encapsulated by an outer part made of heat-resistant plastic with the formation of cooling water and oil-carrying spaces.

From EP-0 067 890 A1 it is known to provide a housing for a multi-cylinder internal combustion engine with side walls made of plastic. Here, the housing is essentially formed from a one-piece metallic frame with liners, crankshaft bearings, a bottom and an upper, closed deck (closed deck) and end-side walls. This structure, which is open on its long sides, is then closed by separately formed plastic side walls.

Furthermore, it is known from DE-43 06 269 A1 to make the housing for a multi-cylinder internal combustion engine divided in such a way that a one-piece inner part is screwed into an outer, trough-shaped housing shell, which consists of a bottom provided with a circumferential flange and molded bushings as well as walls with crankshaft bearings.

In addition, from CH-428 319 an aluminum crankcase with separately used liners is known, the side walls of which are formed by metal plates inserted during the casting of the housing in order to reduce noise emission.

Finally, from DE-OS 17 51 919 a one-story cylinder block for an internal combustion engine with cast-on crankshaft bearings and cast-in stud bolts for fastening a cylinder head is known, the outer shell of which is formed by attached molded parts made of sheet metal or plastic.

The invention has for its object to provide a generic housing for a reciprocating internal combustion engine with an inner and an outer part, which is largely free of distortion and as stiff as possible during operation of the internal combustion engine. In addition, this housing should be lightweight and provided with acoustically advantageous damping properties.

This object is achieved with the features of claim 1. Advantageous refinements of the invention are specified in the dependent claims.

The main advantages of the invention can be seen in the fact that the inner part also receives the liners in one piece, thereby avoiding additional connection points. All of the noise-causing or noise-transmitting components of the inner part are thus to be produced using the same material, for example, from a gray cast iron material which has favorable damping properties.
The essential further component of the housing, the outer part, can be made of a light metal material to reduce the weight of the entire housing, for. B. made of an aluminum or magnesium alloy, and thus has sufficient strength to absorb the forces and moments transmitted from the inner part to the outer part and vice versa, moreover, it is for in an internal combustion engine prevailing operating conditions, in particular comparatively high temperatures and exposure to oil or water.
Alternatively, the outer part can be made of a lightweight plastic.

Advantageously, the screw pipes extend largely free-standing from the liners, so that the vibrations transmitted to the liners by piston side forces are not passed on via these screw pipes. Likewise, vibrations originating from the crank mechanism are kept away from the bushings by means of these screw pipes due to a continuous flow of force. The liners are therefore exempt from the alternating forces between the cylinder head and crank mechanism transmitting power flow and low distortion, which in turn z. B. has a positive effect on oil consumption, wear and blow-by gases.

In an advantageous embodiment, the screw pipes can extend from the deck up to the upper connection level, but alternatively these screw pipes can also be made separately horizontally. Here, a part is assigned to the inner part and extends from the deck in the direction of the upper connection level in such a length that a thread can be introduced, the second part of the screw pipes is arranged in the outer part and is supported on the section assigned to the inner part.

In an advantageous embodiment, irrespective of one-part or multi-part screw pipes, these can be connected to the deck and the bushings near the deck by means of stiffening bridges.
In order to achieve an optimally rigid bond between the inner and outer part, the deck has, in a further embodiment, a claw area on its outer circumferential line, which is largely enclosed by the material of the outer frame during casting. For optimal absorption of longitudinal forces introduced into the housing, for example by means of a gear housing arranged at the end, this claw area can have a circumferential bead which, in a further embodiment, can be designed in a tooth-like manner in sections. In any case, this deck enables an unimpeded, even flow of force for these longitudinal forces, which in turn causes less warpage.

Furthermore, for the purpose of improved clawing, the deck in its area lying between the outer circumferential line and the liners can be provided with openings which are penetrated by the material of the outer part.

In addition to the clawing mentioned in the area of the deck, this housing can have comparable clawing areas on its upper or lower end face in a further advantageous embodiment. For this purpose, the bearing seats for the crankshaft in the area of the lower connection level can have further claw areas which project outwards and which can be connected to one another in the longitudinal direction for the purpose of stiffening.

The end faces of the one-piece screw pipes and / or the bushings assigned to the upper connection level can furthermore have teeth running perpendicular to this upper connection level for the purpose of improved clawing. When joining the inner and outer part, these end faces are completely encapsulated by the material of the outer part, so that a material-uniform cover surface is available for further processing in the area of this upper connection level. This is favorable for the cutting tools to be used and for the resulting chip flow and the recycling of these chips.

Basically, this housing can be designed as an open deck or closed deck. Furthermore, the housing can be produced in die casting, chill casting or sand casting.

During the encapsulation of the inner part, a water jacket core can be arranged directly on the outside of the liners to produce a cooling water jacket, whereby an optimal heat transfer can be achieved.
As an alternative to this, the water jacket core can be arranged at a slight distance from the liners so that a comparatively thin layer of the outer part material is cast around them, thereby creating a self-contained, liquid-tight cooling water-conducting cavity.

Bearing caps held on the bearing chairs are preferably made of the same material, preferably gray cast iron, as the inner part. As a result, cutting-edge manufacturing of the bearing aisle for the crankshaft and an extremely low bearing play can be achieved during operation of the internal combustion engine. A further stiffening and noise reduction can be achieved in that these bearing caps are combined in the form of a one-piece bearing bridge extending over the length of the housing.

Overall, the invention has the advantage that a low-warpage, rigid housing with very good running and damping properties is created with a low weight. The usual effort is eliminated by the additional pressing or pouring of isolated liners or the elaborate machining of the cylinder running surfaces in so-called light metal engines.

In addition, it should be pointed out that the housing has an inner part in the case of an in-line internal combustion engine or a VR engine with several cylinders, while a V-type internal combustion engine can have its own inner part for each cylinder bank, which are then cast together by the outer part.

• Figur 1 eine Draufsicht auf ein Innenteil eines Gehäuses,
• Figur 2 eine Seitenansicht zu Figur 1,
• Figur 3 eine Ansicht von unten auf ein Innenteil eines Gehäuses,
• Figur 4 einen Schnitt entlang der Linie IV - IV gemäß Figur 1,
• Figur 5 einen Schnitt entlang der Linie V - V gemäß Figur 1 durch ein Gehäuse,
• Figur 6 einen Schnitt entlang der Linie VI - VI gemäß Figur 1 durch ein Gehäuse,
• Figur 7 einen Schnitt entlang der Linie VII - VII gemäß Figur 1 durch ein Gehäuse,
• Figur 8 einen Schnitt durch eine andere Ausführungsform ähnlich Figur 4 und
• Figur 9 einen Schnitt durch die geänderte Ausführungsform ähnlich Figur 5.

Further advantages of the invention result from the exemplary embodiment explained in more detail below with reference to a drawing. Show it:

• FIG. 1 shows a plan view of an inner part of a housing,
• FIG. 2 shows a side view of FIG. 1,
• FIG. 3 shows a view from below of an inner part of a housing,
• FIG. 4 shows a section along the line IV-IV according to FIG. 1,
• 5 shows a section along the line V - V according to FIG. 1 through a housing,
• FIG. 6 shows a section along the line VI-VI according to FIG. 1 through a housing,
• 7 shows a section along the line VII-VII according to FIG. 1 through a housing,
• 8 shows a section through another embodiment similar to Figure 4 and
• 9 shows a section through the modified embodiment similar to FIG. 5.

An internal combustion engine has a housing which is essentially formed from an inner part, designated overall by 1, and an outer part 2 cast around it.
The internal combustion engine has cylinders 3, 4 arranged along a longitudinal center plane L, which have bushings 5, 6.

The inner part 1 is made in one piece and of the same material from gray cast iron and essentially consists of the liners 5, 6, a deck 7, screw pipes 8 and bearings 9 for a crankshaft with walls 10 running in transverse planes Q adjacent to the cylinders 3, 4.

According to FIG. 2, the inner part 1 extends essentially between an upper connection level A for a cylinder head (not shown) and a lower connection level B.

It should be pointed out that the terms used in connection with this invention, such as upper or lower, only refer to the drawing figures and in particular do not imply any restriction with regard to a possible installation position of this housing.

The screw pipes 8 extend from the deck 7 to the area of the upper connection level A, while the walls 10 extend essentially from the deck 7 to the lower connection level B.

The sleeves 5 extend in their lower area to a level E lying between the deck 7 and the lower connection level B.
The screw pipes 8 have receptacles 11 and threads 12 for receiving screws (not shown) connecting a cylinder head to the housing.

Threads 13 for fastening crankshaft bearing caps 14 are arranged in each wall 10 on both sides of the bearings 9, these being made of the same gray cast iron material as the inner part 1.

Threads 13 and threads 14 can be aligned axially with one another to improve the flow of force, alternatively continuous tie rods can be used from the bearing caps 14 to the cylinder head.

An integral part of the inner frame 1 is adjacent to the deck 7 a longitudinally extending main oil channel 15, from which, for example, transverse channels 16 branch off to supply the bearings 9.

To achieve a rigid bond, 7 stiffening bridges 17 are cast between the screw pipes 8 and the bushings 5, 6 in the area of the deck.
In the transverse plane Q lying between the cylinders 3 and 4, the wall 10 is guided beyond the deck 7 in the direction of the upper connection plane A while leaving a cooling water passage 18.

To create a positive locking in the transverse and longitudinal direction of the housing between the outer part 2 and the inner part 1, the deck 7 has on its outer circumferential line a claw area 20 which is largely encapsulated by the outer frame 2.
The claw area 20 has a bead 21 which extends at least in sections along the circumferential line of the deck 7 and extends to both sides of this deck 7 and which, as can be seen from FIG. 2, has a tooth-like shape 22.
In order to increase the clawing effect, the deck 7 according to FIG. 1 has openings 23 which are penetrated by the outer part 2 when the outer part 2 is cast around it.
Deviating from the design of the deck 7 shown in the figures, this can run significantly closer to the bushings 5, 6 or the screw pipes 8 and, in so far as it is less plate-like, as can be seen in FIG.

Another claw area 24 is formed on bearing seats 25 of the bearing 9, projecting outward in the form of struts 26 provided with an opening. As shown in FIG. 3, the right half of the figure, these can be connected to one another in the longitudinal direction of the housing by means of cast-on bridges 27.

To provide a claw in the area of the upper connection plane A, the bushings 5, 6 have a toothing 28 in the form of cast-in recesses 29 on their end face 30 facing the plane A.
An identical claw can be provided on the corresponding end faces 31 of the screw pipes 8.
These end faces 30, 31 are completely encapsulated by the outer part material according to FIGS. 5 and 6, so that a cover surface 32 of the same material as that facing the cylinder head is created.

During the encapsulation of the inner part 1, a water jacket core 35 can be arranged at a slight distance from the liners 5, 6 in such a way that they are surrounded by a comparatively thin layer 36.
Alternatively, this water jacket core 35 can also be arranged directly on the liners 5, 6.

In order to provide uniform cooling on the circumference of the bushings 5, 6, a water jacket 37 can be carried out between the screw pipes 8 and the bushings 5, 6, for which purpose the screw pipes 8 can be provided with flats 38 according to FIG. 6.

A finished housing, formed from inner part 1 and outer part 2, can best be seen from FIG. 5, wherein there is a gear flange 40 formed integrally with the outer part 2 for connecting a gear unit to the housing. The claw area 20 and struts 26 are encapsulated by the outer part material, ribs 41 provided with openings in the area of the walls 10 and the bearings 9 being provided for further stiffening of the entire housing.
FIG. 5 also clearly shows the manner in which the deck 7 and outer walls 42 of the outer part 2 delimit an oil-carrying space in the region of the crank mechanism, while above the deck 7 cooling water-carrying spaces are designed in the form of the water jacket 37.

An embodiment modified with regard to the design of the screw pipes 8 is shown in FIGS. 8 and 9. Here, the screw pipes 8 are of split design, a lower part being designed as a threaded piece 81 belonging to the inner part 1 and an upper part being formed as supports 82 having the receptacles 11 and belonging to the outer part 2.
The threads 12, in which the cylinder head screws can engage, are formed in the threaded slug 81.
The threaded slugs 81 and the supports 82 form a shoulder-like system 83, so that an unimpeded, continuous flow of force is also ensured here.
In the case of an open-deck construction, this embodiment offers improved conditions for the encapsulation of the bushings 5.
Furthermore, a further claw area 84 can be seen in these figures in the transverse planes having the storage chairs 25.

Claims (17)

Housing for a reciprocating piston internal combustion engine, with at least one integrally formed, at least one cylinder (3, 4) having, metallic inner part (1), which has a deck (7) formed thereon, in the direction of an upper connection level (A) for has a cylinder head extending screw pipes (8), with walls (10) extending from this deck (7) adjacent to the cylinder (3, 4) in transverse planes (Q) to a lower connection plane (B), which bearing supports (25 ) for a crankshaft, and with an outer part (2) cast around the inner part (1) and forming spaces for cooling water and oil and consisting of a work tunnel deviating from the inner part (1), characterized in that it is integral with the inner part (1) Bushings (5, 6) are formed. Housing according to claim 1, characterized in that the liners (5, 6) extend between the upper connection level (A) and a level (E) lying between the deck (7) and the lower connection level (B). Housing according to Claim 1 or 2, characterized in that stiffening bridges (17) cast on are arranged between the screw pipes (8) and the bushings (5, 6) in the region of the deck (7). Housing according to claim 1, characterized in that the deck (7) has on its circumferential line a claw area (20) which is largely encapsulated by a corresponding area of the outer part (2). Housing according to claim 4, characterized in that further claw areas (24) projecting outwards projecting from the bearing seats (25) are arranged. Housing according to claim 4 or 5, characterized in that a circumferential bead (21) extends at least in sections along the circumferential line. Housing according to one or more of the preceding claims 4 to 6, characterized in that the circumferential line has a tooth-like shape (22) at least in sections. Housing according to one or more of the preceding claims 4 to 7, characterized in that the deck (7) in the claw area (20) has openings (23) penetrated by the outer part material. Housing according to Claim 5, characterized in that the further claw areas (24) are connected to one another in the longitudinal direction of the housing by means of cast-on bridges (27). Housing according to Claim 1, characterized in that end faces (30, 31) of the inner part (1) facing the upper connection plane (A) are cast around by the outer part material in such a way that a uniform surface area (32) facing the cylinder head is produced. Housing according to claim 10, characterized in that at least one of the end faces (30, 31) has a toothing (28) extending perpendicular to the upper connection plane (A). Housing according to claim 1, characterized in that a water jacket core (35) is arranged directly on the bushings (5, 6) during the casting around the inner part (1). Housing according to claim 1, characterized in that a water jacket core (35) is arranged at a slight distance from the liners (5, 6) during the casting around the inner part (1). Housing according to claim 1, characterized in that the bearings (9) of the crankshaft have bearing covers (14), the screw connections arranged on both sides of a longitudinal center plane (L) of the housing are arranged in alignment with the screw pipes (8). Housing according to claim 1 or 14, characterized in that the bearings (9) of the crankshaft have bearing covers (14) which are connected to one another in the manner of a bridge in the direction of a longitudinal center plane (L), these being made of the same material as the inner part (1st ). Housing according to claim 1, characterized in that the screw pipes (8) extend from the deck (7) to the area of the upper connection level (A). Housing according to claim 1, characterized in that the screw pipes (8) are designed so that part is assigned to the inner part (1) as a thread socket (81) and another part is assigned to the outer part (2) as supports (82).

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