JPH04121443A - Cylinder block structure for internal combustion engine - Google Patents

Abstract

PURPOSE:To reconcile insurance of strength and rigidity and reduction in weight by molding a metal cylinder block body and a synthetic resin casing separately, and bolting the lower deck part of the cylinder block body inserted into the casing to the projecting piece of the casing. CONSTITUTION:This cylinder block structure is divided roughly into a cylinder block body 1 made of metal and a casing 2 consisting of epoxy resin or phenol resin. This cylinder block body 1 has a plurality of cylindrical cylinder parts 3, lower deck parts 4 formed on their lower ends, a cylinder head part 6, and a bearing support part 7. The casing 2 has a box water jacket outer wall 21 covering the circumference of the cylinder parts 3, a skirt part 22 swollen outward from the lower end thereof, projecting pieces 24 protruded inward along the lower end of the water jacket outer wall 21. The lower deck parts 4 of the cylinder block body 1 are put on the projection pieces 24 through caskets 31 and bonded thereto by bolts 13.

Description

[Detailed description of the invention] Industrial applications The present invention relates to a cylinder block structure for an internal combustion engine.

BACKGROUND OF THE INVENTION The main body of an internal combustion engine is roughly divided into a cylinder block and a cylinder head, and in automobile engines, each is generally cast as one piece using cast iron, aluminum alloy, or the like.

However, such a structure made entirely of metal is heavy, so in recent years, various cylinder block structures made partially of synthetic resin have been proposed in order to reduce the weight.

For example, in Japanese Utility Model Application Publication No. 61-76149, a cylinder lychee portion in which a plurality of cylinders are arranged in a row and a main bearing portion integrated with a skirt portion are each made of metal, and the periphery of the cylinder lychee portion is A cylinder block structure is disclosed in which the outer wall of a box-shaped water jacket surrounding the cylinder is made of synthetic resin, specifically FRP.

Further, Japanese Utility Model Publication No. 61-76144 discloses a cylinder block structure in which the outer wall of the water jacket and the skirt portion are made of synthetic resin.

Problems to be Solved by the Invention However, in the above-mentioned conventional configuration in which a part of the cylinder block with a separate cylinder head, such as the outer wall of the water jacket, is made of synthetic resin, the cylinder head cannot be attached to the cylinder head with the cylinder head bolts. When fastened, a large load is applied to the outer wall of the synthetic resin water jacket, which may cause distortion especially at high temperatures, leading to water leakage from the water jacket.

In addition, Utility Model Application Publication No. 62-69046 and Utility Model Application No. 62-38
No. 459 discloses a cylinder block structure in which a cylinder head portion is integrated with a cylinder portion, but these are entirely made of metal and cannot be expected to be lightweight.

Furthermore, when the water jacket outer wall and the like are made of synthetic resin as described above, it is easy to have a problem with how to firmly connect the transmission and engine mount bracket.

Means for Solving the Problems A cylinder block structure for an internal combustion engine according to the present invention includes a plurality of cylindrical cylinder parts, a lower deck part located at the lower end of the cylinder part, and a combustion engine that closes the upper end of the cylinder part. A cylinder head portion defining a chamber and a bearing support portion extending below the lower deck portion at a position between the cylinders are integrally molded from metal to form a cylinder block body, and the cylinder portion is a water jacket outer wall that covers the water jacket to define a water jacket; a skirt portion that includes a rib on the inner side that fits into the bearing support portion; and a protrusion piece that is formed to protrude inwardly along the lower end of the water jacket outer wall; are integrally molded with synthetic resin to form a casing, the upper end of the outer wall of the water jacket is fitted and fixed to the lower surface of the cylinder head via a sealing member, and the lower deck portion and the protruding piece are bolted together. The cylinder block body and the casing are integrated.

Further, as a coupling portion to the transmission, a substantially arc-shaped metal reinforcing plate protruding outward from the outer wall of the water jacket is disposed at one end of the casing, and a boss portion for coupling the transmission is formed on the reinforcing plate. At the same time, a boss portion for coupling the transmission is also formed on the outer wall surface of the cylinder portion located on the reinforcing plate side, and the transmission is coupled with bolts across both parts.

In addition, as a connection part of the mount bracket, a side bolt is provided that passes through the rib and is screwed into the bearing support part. It is now connected to the section.

Effect: In the above configuration, the cylinder block body and the casing are separately molded in advance, and the cylinder block body is inserted into the casing. Then, the lower deck portion of the cylinder block body and the projection piece of the casing are bolted together to integrate them.

In this cylinder block structure, the parts that receive combustion pressure and bearing load, that is, the cylinder part, cylinder head part, and bearing support part, are made of metal and are therefore lightweight, and at the same time, high strength and rigidity are achieved.

Further, a portion of the transmission is supported by the casing via a reinforcing plate, and a portion is directly supported by the boss portion of the cylinder block body.

Further, the mount bracket is firmly supported by the metal cylinder block body across the pair of bearing support parts.

EXAMPLE Hereinafter, an example of the present invention will be described in detail based on the drawings.

FIG. 1 shows an embodiment of a cylinder block structure according to the present invention. This cylinder block structure is roughly divided into a cylinder block body 1 made of metal, and a casing 2 made of epoxy resin, phenol resin, or FRP (fiber reinforced resin) mainly made of these resins.

As shown in FIGS. 2 to 4, the cylinder block main body 1 includes four cylindrical cylinder sections 3 arranged in series.
A lower deck portion 4 formed in a flange shape at the lower end of the cylinder portion 3, a cylinder head portion 6 that closes the upper end of the cylinder portion 3 to define a combustion chamber 5, and a lower deck portion 4 at a position between the cylinders. 4 and a bearing support portion 7 extending downwardly, and the entirety thereof is integrally cast from aluminum alloy or the like.

The cylinder head portion 6 is formed with an intake port 8, an exhaust port 9, a water jacket 10, and the like. Furthermore, a groove 11 is formed on the lower surface projecting outward from the cylinder portion 3 and is continuous over the entire circumference.

Further, on the outer circumferential surface of the intermediate portion of the cylinder portion 3, reinforcing plate support portions 12 consisting of a pair of upper and lower protrusions are provided partially, as shown in FIG. .

As shown in FIG. 3, the lower deck portion 4 has a rectangular shape, and screw holes 14 into which bolts 13 for fixing the casing 2 are screwed are formed at a plurality of locations.

The bearing support part 7 has a substantially rectangular shape with gently tapered sides on both sides, and a semicircular main bearing part 15 is recessed in the lower edge of the bearing support part 7, and a side bolt 16 is provided on both sides. A screw hole 17 is formed. Incidentally, as shown in FIG. 1, each bearing cap portion 19 of the bearing beam 18 is assembled to the bearing support portion 7 using a pair of cap bolts 20, respectively.

On the other hand, as shown in FIGS. 5 to 7, the casing 2 includes a substantially rectangular box-shaped water jacket outer wall 2 that covers the periphery of the cylinder portion 3, and a lower end of the water jacket outer wall 21 extending outward. A half-skirt type skirt portion 22 formed in a swollen manner, and a bearing support portion 7 formed inside the skirt portion 22 at a position between the cylinders.
Lips 23 that fit on both sides, and protrusion pieces 2 that are formed to protrude inward along the lower end of the water jacket outer wall 21.
4, all of which are integrally molded from the resin material mentioned above.

The water jacket outer wall 21 has a reinforcing plate 2 which will be described later.
The intermediate height portion has a cross-sectional shape that is slightly convex inward so as to firmly support the base plate 5 (see FIG. 7).

Further, as shown in FIG. 5, the projection piece 24 is formed over the entire circumference, and through holes 26 are provided at positions corresponding to the screw holes 14 of the lower deck portion 4. Note that this protrusion piece 24 is partially provided with a notch 24a (see FIG. 5) in order to avoid interference with the bearing support part 7.

The ribs 23 have approximately the same wall thickness as the bearing support portion 7, and are provided with through holes 27 for the side bolts 16, respectively. Additionally, side bolts 16 are attached to the outer surface of the skirt portion 22.
A boss portion 28 is formed to receive the head of the holder.

FIG. 8 shows a frame-shaped reinforcing plate 25 held between the cylinder portion 3 on the cylinder block body 1 side and the water jacket outer wall 21 on the casing 2 side. This reinforcing plate 25 is molded from epoxy resin, phenolic resin, etc., and is formed into a shape that is divided into left and right halves as shown in the figure. It is designed to be incorporated in between. The reinforcing plate 25 has a shape that leaves a cooling water flow path in the shaded area in FIG. 8, and communication holes 29 are formed through the reinforcing plate 25 at appropriate positions to adjust the flow of cooling water. ing.

The cylinder block main body 1 configured as described above is inserted into the casing 2 from above and assembled integrally. Specifically, the upper end of the water jacket outer wall 21 is fitted into the groove 11 of the cylinder head 6 via the seal member 30 and is fixedly supported. In addition, the lower deck portion 4 of the cylinder block body 1 is connected to the protruding piece 24 of the casing 2.
They are stacked on top of each other with a gasket 31 interposed therebetween, and are connected to each other by bolts 13 from the lower crankcase side. As a result, the water jacket 32 is disposed between the water jacket outer wall 21 and the cylinder part.
is defined, and a reinforcing plate 25 is disposed in the middle thereof. This water jacket 32 is connected to the cylinder head portion 6
It also communicates with the water jacket 10 inside.

Note that the cooling performance can be improved by making the communication holes 29 of the reinforcing plate 25 different on the exhaust side and the intake side, for example.

Further, the bearing support portion 7 is fitted between the ribs 23 on the inside of the skirt portion 22 on both sides, and is firmly connected to each rib 23 by a glass 1' dolt 16 on the outside of the skirt portion 22.

Therefore, according to the configuration of this embodiment, the cylinder head section 6, cylinder section 3, main bearing section 7, etc. that receive combustion pressure and bearing load are made of metal and have extremely high strength. Stiffness can be obtained. In particular, during a combustion explosion, an upward force acts on the cylinder head section 6 and a downward force acts on the main bearing section 7, but the tensile force between them is supported by the cylinder section 3, which is integrated with both. No large force is applied to the water jacket outer wall 21, and there is no risk of water leakage.

As mentioned above, the water jacket outer wall 21 is bent inward in the free state, and as a result, it tries to strongly clamp the reinforcing plate 25, so that it is firmly supported by the cylinder part 3 via the reinforcing plate 25. shape, ensuring sufficient strength even in the middle part.

In addition, since the skirt portion 22 is firmly supported by the main bearing portion 7, its vibration is suppressed and does not become a source of noise including the oil pan (not shown) attached to the lower edge.

Furthermore, since a considerable portion of the casing 2 can be made of synthetic resin, a significant weight reduction can be achieved.

Next, FIG. 9 shows a different embodiment of the invention. In this embodiment, a stepped portion is formed at the upper end of the water jacket outer wall 21 by a projection piece 21a on the outer peripheral edge, and this stepped portion is adapted to fit into the lower surface of the cylinder head portion 6. An O-ring-shaped sealing member 41 made of, for example, rubber is interposed between the joint surfaces of the two. Further, a rubber washer 42 is provided on the bolt 13 screwed into the lower deck portion 4, so that leakage of cooling water transmitted through the poles 1-13 is more reliably prevented. In addition, bolt 13
If you apply an anaerobic adhesive or the like to the threaded portion of the tube before screwing it on, water leakage can be more effectively prevented.

Next, in the embodiment shown in FIGS. 10 to 13, the bearing support part 7
A dovetail-shaped protrusion 43 is formed along the vertical direction on both sides of the casing 2, and a dovetail-shaped groove 44 that can be engaged with the protrusion 43 is formed on the inner surface of the lip 23 of the casing 2. .

According to this embodiment, by inserting the cylinder block body 1 into the casing 2 from above, the protrusion 43 of the bearing support part 7 and the groove 44 of the rib 23 fit together while sliding, and both are firmly attached. will be integrated into. Therefore, the side bolts 16 can be omitted, and assembly is also simplified.

Incidentally, as shown in FIG. 14, a projection 43 having a substantially circular cross section and a corresponding groove (not shown) may be formed. Further, it is also possible to form a protrusion on the rib 23 side and a groove on the bearing support part 7 side.

Next, the transmission coupling portion in the cylinder block structure using the metal cylinder block body 1 and the synthetic resin casing 2 as described above will be explained.

FIGS. 15 to 17 show an embodiment of this transmission coupling part, in which the transmission coupling part is installed at the rear end of the synthetic resin casing 2 in a form that is integrated with the rear end wall 21b of the water jacket outer wall 21. An arc-shaped metal reinforcing plate 51 is insert molded.

This reinforcing plate 51 is connected to the left and right water jacket outer walls 21.
It protrudes further outward and is supported by ribs 52 formed diagonally protruding on both sides of the casing 2, and metal boss portions 5 are provided at two locations on the left and right of the peripheral edge thereof.
It has 3. The boss portions 53 each have a screw hole 54.

Further, one boss portion 55 is provided in the cylinder portion 3 on the cylinder block body 1 side. Specifically, a boss portion 55 is formed on the outer wall surface of the cylinder portion 3 located at the rearmost end of the engine, and projects toward the rear end wall 21b of the water shelter outer wall 21, and a screw hole 56 is provided in the boss portion 55. ing. A through hole 57 is formed in the rear end wall 21b of the water jacket outer wall 21 in correspondence with the boss portion 55, and a heat-resistant elastic material is provided on both surfaces between the boss portion 55 and the rear end wall 21b. A packing 58 with a .

Using the five boss portions 53 and 55 configured as described above, the transmission 59 is coupled with bolts 60 as shown in FIGS. 18 and 19.

Therefore, according to this configuration, the central portion of the transmission 59 is directly coupled to the highly rigid cylinder portion 3, and sufficient coupling rigidity can be obtained. Further, by providing the central boss portion 55 on the cylinder portion 3 side, the cylinder block body 1 and the casing 2 can be assembled without any trouble.

Next, FIG. 20 and FIG. 21 show the joint portion of the mount bracket 61 for supporting the engine on the vehicle. A bolt 62 is provided.

This side bolt 62 passes through the rib 23 and is screwed into the bearing support part 7, and there are a total of four side bolts 62.
The plate portion 61a of the mount bracket 61 is fixedly supported. In addition, the above mount bracket 61
are arranged to be inclined with respect to the axis of the side bolt 62, so boss portions 63 and 64 corresponding to the inclination are formed on the outer surface of the skirt portion 22 and on the plate portion 61a, respectively.

Effects of the Invention As is clear from the above explanation, according to the cylinder block structure of an internal combustion engine according to the present invention, a considerable number of parts can be made of synthetic resin with almost no load being applied to the synthetic resin parts. Significant weight reduction can be achieved. In particular, by integrating the cylinder head, cylinder, and bearing support with metal, combustion pressure does not act on the synthetic resin water jacket outer wall, etc., ensuring strength and rigidity while reducing weight. can.

Furthermore, it is possible to ensure sufficiently high joint rigidity with the transmission and engine mount without sacrificing weight reduction.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of the entire engine showing one embodiment of the cylinder block structure according to the present invention, FIG. 2 is a sectional view of the cylinder block body, and FIG. 3 is a sectional view taken along the m-axis in FIG. Figure 4 is a side view of the main part of the cylinder block body.
FIG. 5 is a sectional view of the casing, FIG. 6 is a side view, FIG. 7 is a sectional view of the main part of the casing, FIG. 8 is a plan view of the reinforcing plate, and FIG. 9 shows a different embodiment of the invention. Fig. 10 is a sectional view of the cylinder block body showing a further different embodiment, Fig. 11 is a sectional view taken along the C-C line, and Fig. 12 is a sectional view of the casing in this embodiment. 13 is a side view, FIG. 14 is a sectional view similar to FIG. 11 showing an example of a change in the shape of the protrusion, FIG.
Figure 6 is a side view of the main parts, Figure 17 is a front view of the rear end, Figure 18 is a plan view with the transmission attached, Figure 19 is a front view, and Figure 20 is the mount bracket joint. FIG. 21 is a front view of the main part, and FIG. 21 is a side view of the main part. 1... Cylinder block body, 2... Casing,
3... Cylinder part, 4... Lower deck part, 6...
Cylinder head part, 7... Bearing support part, 21... Water jacket outer wall, 22... Skirt part, 51...
...Reinforcement plate, 53.55...Boss part, 61...Mount bracket, 62...Side bolt. Figure 2 Figure 9 Figure 1θ Figure 1'3 Figure 11 Figure 18 Figure 19

Claims (3)

[Claims] (1) A plurality of cylindrical cylinder parts, a lower deck part located at the lower end of the cylinder part, a cylinder head part that closes the upper end of the cylinder part to define a combustion chamber, and the lower deck part at a position between the cylinders. a bearing support part extending below the cylinder part; a water jacket outer wall integrally molded of metal to form a cylinder block body; and a water jacket outer wall covering the cylinder part to define a water jacket; The casing is constructed by integrally molding a skirt portion with a rib on the inside that fits into the outer wall of the water jacket, and a protruding piece formed inwardly protruding along the lower end of the outer wall of the water jacket, and integrally molding the same with a synthetic resin. The upper end of the outer wall of the water jacket is fitted and fixed to the lower surface of the cylinder head via a sealing member, and the lower deck portion and the protruding piece are connected with bolts to integrate the cylinder block body and the casing. Cylinder block structure of an internal combustion engine. (2) At one end of the casing, a substantially arc-shaped metal reinforcing plate that protrudes outward from the outer wall of the water jacket is provided, and a boss portion for coupling the transmission is formed on the reinforcing plate, and the reinforcing plate 2. The cylinder block structure for an internal combustion engine according to claim 1, wherein a boss portion for coupling the transmission is also formed on the outer wall surface of the cylinder portion located on the side, and the transmission is coupled with bolts across both. (3) A side bolt is provided that penetrates the rib and is screwed into the bearing support part, and the mount bracket disposed on the outside of the skirt part is connected to a pair of adjacent bearing support parts by this side bolt. A cylinder block structure for an internal combustion engine according to claim 1.