JPH037021B2 - - Google Patents

Description

[Detailed description of the invention] [Technical field of invention] The present invention relates to an internal combustion engine.

[Prior art]

In conventional internal combustion engines, the head is fixed to the top of the cylinder block and the crankshaft bearing is fixed to the bottom of the cylinder block. Due to the pressure pulsations occurring within the cylinder, high tension loads are transmitted through the cylinder block. To avoid this, it has been proposed to provide long bolts or studs for fixing the cylinder head to the cylinder block. These long bolts or studs are fixed to the bearing structure of the crankshaft (US Pat. No. 3,173,407 and French Patent Specification No. 2,022,295). Since the tension loads are supported by long bolts or studs, long tensile strength materials can be used for the cylinder block itself.

For example, in order to facilitate production by die casting, it has been proposed to make the cylinder block and crankcase of an internal combustion engine in two parts divided about a plane containing the axes of adjacent cylinders (British patent specification Book No. 858593).

[Summary of the invention]

The invention provides that the housing for each crankshaft bearing is divided into two halves, and the two halves meet in a plane containing the axis of the adjacent cylinder, in order to hold each pair of bearing housing halves together. Each is provided with a yoke and tension members are provided to secure the cylinder head to the cylinder block, the tension members extending to the yoke to provide an internal combustion engine secured to the yoke.

Achieving the advantages of a tension member (allowing the use of lightweight, high tensile strength materials for the cylinder block) by providing a yoke for holding together the pair of shaft housing halves, to which the tension member is fixed; , it becomes possible to achieve the advantages (easiness of manufacture) of a cylinder block structure divided around a plane containing the axes of adjacent cylinders. Therefore, the main body of the cylinder block can be made of a low tensile strength material, such as an aluminum alloy or a plastic material, since the yoke surrounding the crankshaft bearing and the tension member themselves withstand high tensile stresses. Each yoke may include a clamping member extending generally in the same direction as the tension member extends and a lateral fixture clamping the clamping members together.
The clamping member is positively positioned against movement in the direction of the tension member relative to the crankshaft bearing housing half. By doing this, movement of the clamping member due to loads applied during engine operation is avoided, and thus the risk of the transverse fasteners being severed is avoided. To prevent relative movement of the parts, the interface between the crankshaft bearing housing half and the clamping member can be curved (e.g. parallel to the surface of the bearing housing) or the mating surfaces of the mating teeth can be A mechanical key such as this can be provided preferably in the area of the transverse fastener.

The cylinder block can have two parts connected to each other in a plane and a cylinder with a liner. Each section is integral with its respective bearing housing half. At least one of the crankcase and the oil sump can also consist of two parts connected to each other in a plane. Each part is integral with its respective part of the cylinder block, which makes it easy to manufacture each part.

The internal combustion engine of the present invention can be a spark ignition internal combustion engine or a compression ignition internal combustion engine.

〔Example〕

Hereinafter, the present invention will be explained in detail with reference to the drawings.

In conventional internal combustion engines, the cylinder head is bolted to the top of the cylinder block and the main (crankshaft) bearing cap is bolted to the bottom of the cylinder block. The pressure pulse generated by the explosion stroke creates a stress transmission path between the cylinder head bolt and the bearing cap bolt. The stress transmission path extends directly inside the cylinder block. Conventional cylinder blocks are often made of cast iron or aluminum alloys; however, cast iron is inherently brittle and is therefore more susceptible to tensile than compressive loads, whereas aluminum alloys are more susceptible to stretching under tension.

First, please refer to FIGS. 1 to 3. These figures show the integral block crankcase and sump structure of an inline three-cylinder engine. This engine structure is divided into two halves 1 and 2 around a plane containing the axis of the cylinder. The engine has a liner 3. The liner 3 of FIG. 1 is cooled by a water or oil jacket 4 formed by the thin outer wall 5 of the engine. Liner 3 is not shown in FIGS. 2 and 3.

Crankshaft with three bends (not shown)
is supported by four bearings. Each engine/
Halfs 1 and 2 are each bearing housing half 6,
form 7. Each bearing housing half includes two planar bearing shell halves (not shown) that form bearings for the crankshaft. Bearing housing・
The halves are held together by a yoke consisting of steel clamping members 8, 9 and transverse fasteners consisting of steel bolts 12, 13. The yoke is inserted into a recess 10 in the flanged outer wall of the engine structure. Bolts 12 and 13 are for engine half 1,
2 through the holes 12a, 13a provided in each of the holes 12a, 13a, respectively, to tighten the clamping members 8, 9 together. The engine halves are also held together by bolts (not shown) and bolts 23 that pass through holes 25, 26.

The tightening members 8, 9 receive long tension members (female) consisting of steel bolts 14, 15.
A thread is also formed. Bolts 14, 15 are screwed into the top of the cylinder head (not shown).
The bolts 14, 15 are passed through holes 14a, 15a drilled in the engine halves 1, 2. Studs may be used instead of bolts if desired.

With this configuration, the stress caused by the pressure pulsations in the cylinder that appears between the cylinder head and the main bearing can be absorbed by the long steel bolts 14, 1.
5, steel yokes 8 and 9, and steel bolts 12 and 13. The engine structure itself (the two halves) can be made of lighter and thinner materials than those used in conventional engines, since they are kept under nearly compressive loads and do not support tensile stresses.

To reduce weight, the walls of crankcase 16 are kept to a minimum thickness and are provided with a number of ribs, such as ribs 17, for reinforcement.

Lubrication of the bearing is carried out through the passage 19, the chamber 20,
Gearry 1 that supplies lubricating oil via passage 21
8.

The support rib 22 and the rib housing the lubricating oil passage 19 transfer the remaining bottom end load to the steel tension member 2.
Tell 3. The member 23 extends within the hole 23a.

Internal pumping pressure that may exist between one cylinder and another is vented through the holes 24.

The walls 34 and 35 (Fig. 2) have a planar shape of U.
Form a space of form. The space is communicated with the space below the piston by a hole (not shown) in the end wall of the crankcase. This allows for ventilation between the crankcase and the valve gear cover of the cylinder head (not shown) (which can be forced ventilation using suction traction low pressure) and for lubricating oil from the valve gear cover to the sump. It is possible to return the . Alternatively, those walls can be eliminated and the ventilation passages and lubricant return passages provided elsewhere.

Engine halves 1, 2 are made of aluminum alloy. There are no undercuts in any of the engine halves, and the engine halves are pressure die cast. The traditional casting of cylinder blocks using sand molds is eliminated. A wide selection of alternative materials and alternative manufacturing methods is possible. The engine half can therefore be made of sand die-casting or gravity die-casting using an aluminum alloy, or sand die-casting or die-casting (pressure die-casting or gravity die-casting) using a magnesium alloy. Alternatively, the engine half can be made of plastic such as polyester or phenolic resin. Thermosetting plastics such as urea resins or polyimides (with or without reinforcing agents) can be used to make injection molded or stamped molded materials. Those materials are
Usually, it is a powder in its raw material state. Alternatively, you can omit some ribs and make the engine half a steel plate,
Alternatively, SMC or molded composite board (usually polyester) or DMC or duff molded composite (usually polyester) can be used. Furthermore, conventional materials such as cast iron can also be used.

Gear rally 18 and holes 25, 26, 12a, 1
3a, 23a, 14a, 15a, 19 can be formed by drilling or by integral molding during a molding or casting operation. A dowel is then inserted into the hole 20 by the ram to align the engine halves when they are joined. The top of the engine and both ends face each other. The main bearing housings 6 and 7, which were intentionally made to have a small diameter, are expanded to the correct diameter. Also,
A kneading is performed to receive each liner 3. The engine halves are then separated, the bearing shell halves are inserted, and the cylinder liner 3, piston, connecting rod and crankshaft are installed on one of the engine halves. Apply RTV rubber or a similar sealing compound (e.g. anaerobic compound) onto the periphery of the engine half and tighten the engine half using a yoke and bolts. Finally, place the cylinder head (not shown) on top of the structure and
Thread the long steel bolts 14, 15 into the screw holes of the tightening members 8, 9.

The present invention can be used with various numbers of cylinders, and can also be used with horizontally opposed engines rather than in-line engines, or engines with other in-line configurations, as long as the cylinders are arranged in one plane. . The present invention can be used with compression ignition engines as well as spark ignition engines. Also, the crankcase and oil sump do not need to be integrated with the block. Separate crankcases and oil sumps can be used if desired.

Reference is now made to FIG. 4 in which a three cylinder engine is shown. The arrangement of the cylinders is indicated by dashed lines 27-29. The cylinder head is indicated by dashed line 30. The engine shown in FIG. 4 is similar to the engine shown in FIGS. 1-3, except that the crankshaft bearing between the first and second cylinders counted from the left in the figure is omitted. The bearing housing halves 6, 7 and the corresponding yokes 8, 9, 12, 13 are therefore also omitted.

Due to the cylinder head mounting bolts between the first and second cylinders, one The cylinder head mounting bolt 31 between the first and second cylinders is screwed into the boss 33. The boss 33 is integrally formed with the integral engine structure and the rib 32 that contacts the cylinder head 30. Therefore, the ribs 32 are loaded compressively and the impact forces applied to the cylinder head act on the cylinder head in a compressive rather than a tensile manner due to the construction of this engine. Thus, although one bearing is omitted, lighter and thinner materials can be used since the engine structure is kept in a substantially compressed rather than tensile load. Integral rib 32
and bosses 33 are formed on each engine half, 2
It will be seen that a book bolt 31 is used. Other types of bearings may be omitted, and different configurations may be used depending on the number of cylinders.

Reference is now made to FIG. 5, which shows a different embodiment of the interface between the tension member and the crankshaft bearing housing half than that shown in FIGS. 1-3 and 4.

A horizontal tooth portion 8a is provided on the steel fastening member 8,
Those horizontal teeth 8a on the bearing housing half
A horizontal tooth portion 6a is provided which engages with the horizontal tooth portion 6a. The teeth 6a and 8a together form a mechanical key.

Breaking forces between the clamping members 8, 9 and the main bearing housing halves are resisted by mechanical keying. In the structures shown in FIGS. 1 to 3 and 4, the joint surfaces between the fastening members 8 and 9 and the main bearing housing half are smooth, and the steel bolts 1
The tightening force of 2 and 13 prevents relative movement between the two. However, certain materials for the cylinder block, such as aluminum, can cause brinelling, and aluminum can cause constriction, causing bolts 12,
The thickness in direction 13 may be permanently reduced.
This would allow relative movement and there would be a risk that the transverse bolts 12, 13 would be torn off, since the forces transmitted via the steel bolts 14, 15 would not be properly constrained.

Instead of providing teeth on the cylinder block, the surfaces of the block are smoothed and clamping members 8, 9 made of extremely hard steel are used, during or before assembly, the teeth provided on the clamping members 8, 9 It is also possible to form corresponding teeth on the face of the cylinder block.

The teeth can be horizontal as shown, or
It can also be diagonal, crosshatched, or herringbone shaped.

For the crankshaft bearing housing half,
Another way of ensuring the position of the clamping member against movement in the direction of the tensioning member is shown in FIG. Here, the joint surfaces of the clamping member 8 and the crankshaft bearing housing half 6 are curved in a direction parallel to the surface of the bearing housing, ie rounded.

[Brief explanation of the drawing]

In Figure 1, the part above line A-A is cut along a line passing through the axis of the cylinder, and the part below line A-A is cut along a line passing through the crankshaft bearing structure between the cylinders. FIG. 2 is a perspective view of one half of the integral engine structure showing the inside of the cylinder; FIG. The diagram shows the outside of the engine.
a partially cutaway perspective view of the same half of the integral engine structure; FIG. 4 is a schematic representation of a second engine;
FIG. 5 is a perspective view showing another structure of the joint surface of the tension member and the crankshaft bearing housing, and FIG. 6 is a sectional view showing still another structure of the joint surface of the crankshaft bearing and the tension member. 1, 2... Engine half, 3... Cylinder liner, 6, 7... Crankshaft bearing housing half, 8, 9... Tightening member, 12, 13,
14, 15, 23... Bolt, 8a... Teeth.

Claims (1)

Claims: 1. The housing for each crankshaft bearing is divided into two halves, and the two halves meet in a plane containing the axis of the adjacent cylinder, holding each pair of bearing housing halves together. An internal combustion engine, characterized in that a yoke is provided for each cylinder head, and tension members are provided for fixing the cylinder head to the cylinder block, the tension members extending up to and being fixed to the yoke. 2. The internal combustion engine according to claim 1, wherein each yoke includes a tightening member extending generally in the same direction as the tension member and a lateral direction clamping the tightening members together. An internal combustion engine characterized by comprising: 3. An internal combustion engine according to claim 2, wherein the clamping member is reliably positioned relative to the crankshaft bearing housing half to resist movement in the direction of the tension member. An internal combustion engine characterized by: 4. The internal combustion engine according to claim 3, wherein the joint surface between the crankshaft bearing housing half and the fastening member is curved. 5. The internal combustion engine according to claim 2 or 3, characterized in that a mechanical key fixing means is provided between the crankshaft bearing housing half and the tightening member. Internal combustion engine. 6. Internal combustion engine according to claim 5, characterized in that the mechanical keying means are provided in the region of the transverse fastener. 7. The internal combustion engine according to claim 6, wherein the mechanical key fixing means is comprised of teeth that mesh with each other. 8. The internal combustion engine according to any one of claims 1 to 7, wherein the cylinder block has two parts connected to each other in a plane and a cylinder having a liner, An internal combustion engine characterized in that said parts are integral with their respective bearing housing halves. 9. The internal combustion engine according to claim 8, wherein the cylinder block and the crankcase are integral with each other and have two parts connected to each other in a plane. 10. The internal combustion engine according to claim 9, wherein the cylinder block, crankcase, and oil sump are integral with each other and have two parts connected to each other in a plane. Features an internal combustion engine. 11. An internal combustion engine according to any one of claims 8 to 10, characterized in that the two parts do not have an undercut to facilitate molding or casting of the two parts. Internal combustion engine.